• Journal of Korea Foundry Society
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• v.32 no.1
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• pp.16-23
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• 2012

In this study, we develop the lower pressure die casting with rheo-forming process of A356 aluminum alloy and vacuum system which can control the crystal size and obtain the high strengthened-light material. Using this process, we fabricate the thin plate for bipolar plate through the low pressure die casting with electromagnetic stirring and vacuum-evacuation which can control the crystal grain by electromagnetic stirring. Thin plate ($110mm{\times}130mm{\times}1mm$) is fabricated by this process. The average Vickers hardness of thin plate is about 77 HV.

• Steel and Composite Structures
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• v.27 no.2
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• pp.177-184
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• 2018

This study contributes to evaluate multiphase topology optimization design of plate-like structures on elastic foundations by using classic plate theory. Multi-material optimal topology and shape are produced as an alternative to provide reasonable material assignments based on stress distributions. Multi-material topology optimization problem is solved through an alternative active-phase algorithm with Gauss-Seidel version as an optimization model of optimality criteria. Stiffness and adjoint sensitivity formulations linked to thin plate potential strain energy are derived in terms of multiphase design variables and Winkler-Pasternak parameters considering elastic foundation to apply to the current topology optimization. Numerical examples verify efficiency and diversity of the present topology optimization method of elastic thin plates depending on multiple materials and Winkler-Pasternak parameters with the same amount of volume fraction and total structural volume.

• Journal of Korea Foundry Society
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• v.32 no.1
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• pp.24-31
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• 2012

In this study, semi-solid thin plate of A 356 aluminum alloy was fabricated by using slope plate apparatus and vacuum pressurization. Slope plate was used to produce semi-solid material with spheroidal microstructures. After molten metal was poured into the slope plate connected to the pouring hole of die, semi-solid material flowed into the die cavity by vacuum degree. The primary crystals of the cast metal became spheroidal. In order to increase the working pressure, gas pressurization of U shape was designed for fabrication of thin plate. For 3 bar of gas pressure and 60 mmHg of vacuum degree, thin plate was fabricated without defects on surface.

• Structural Engineering and Mechanics
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• v.61 no.4
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• pp.437-440
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• 2017

This study investigates the bending of an isotropic thin rectangular plate in finite deformation. Employing hyperelastic material of John's type, a non-classical model which generalizes the famous Kirchhoff's plate equation is obtained. Exact solution for deflection of the plate under sinusoidal loads is obtained. Finally, it is shown that the non-classical plate under consideration can be used as a replacement for Kirchhoff's plate on an elastic foundation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.1
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• pp.39-46
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• 2000

An analysis of the free vibration for the metal-piezoceramic laminated thin plates is described. The purpose of this study is to develop a equivalent method for the free vibration analysis of metal-piezoce-ramic laminated thin plate which are not sysmmetric about the adhered layer and the piezoelectric effect. In order to confirm the validity of the vibration analysis, double Fourier sine series is used as a modal displacement function of a metal-piezoceramic laminated thin plate and applied to the free vibration analysis of the plate under various boundary conditions.

• Korean Journal of Materials Research
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• v.32 no.10
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• pp.414-418
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• 2022

Magnesium alloy is the lightest practical metal. It has excellent specific strength and recyclability as well as abundant reserves, and is expected to be a next-generation structural metal material following aluminum alloy. This paper investigated the possibility of thin plate fabrication by applying a overheating treatment to the melt drag method, and investigating the surface shape of the thin plate, grain size, grain size distribution, and Vickers hardness. When the overheating treatment was applied to magnesium alloy, the grains were refined, so it is expected that further refinement of grains can be realized if the overheating treatment is applied to the melt drag method. By applying overheating treatment, it was possible to fabricate a thin plate of magnesium alloy using the melt drag method, and a microstructure with a minimum grain size of around 12 ㎛ was obtained. As the overheating treatment temperature increased, void defects increased on the roll surface of the thin plate, and holding time had no effect on the surface shape of the thin plate. The fabricated thin plate showed uniform grain size distribution. When the holding times were 0 and 30 min, the grain size was refined, and the effect of the holding time became smaller as the overheating treatment temperature increased. As the overheating temperature becomes higher, the grain size becomes finer, and the finer the grain size is, the higher the Vickers hardness.

• Steel and Composite Structures
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• v.44 no.5
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• pp.633-649
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• 2022

This paper is first implemented with the bending behavior of three-dimensional functionally graded (3DFG) plates in the framework of level set-based topology optimization (LS-based TO). Besides, due to the suitable properties of the current design domain, the thin-plate spline (TPS) is recognized as a RBF to construct the LS function. The overall mechanical properties of the 3DFG plate are assessed using a power-law distribution scheme via Mori-Tanaka micromechanical material model. The bending response is obtained using the first-order shear deformation theory (FSDT). The mixed interpolation of four elements of tensorial components (MITC4) is also implemented to overcome a well-known shear locking problem when the thickness becomes thinner. The Hamilton-Jacobi method is utilized in each iteration to enforce the necessary boundary conditions. The mathematical formulas are expressed in great detail for the LS-based TO using 3DFG materials. Several numerical examples are exhibited to verify the efficiency and reliability of the current methodology with the previously reported literature. Finally, the influences of FG materials in the optimized design are explained in detail to illustrate the behaviors of optimized structures.

• Wind and Structures
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• v.25 no.1
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• pp.25-38
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• 2017

This study investigates the dynamic analysis of a transversely isotropic thin plate. The plate is made of hyperelastic John's material and its constitutive law is obtained by taken the Frechect derivative of the highlighted energy function with respect to the geometry of deformation. The three-dimensional equation governing the motion of the plate is expressed in terms of first Piola-Kirchhoff's stress tensor. In the reduction to an equivalent two-dimensional plate equation, the obtained model generalizes the classical plate equation of motion. It is obtained that the plate under consideration exhibits harmonic force within its planes whereas this force varnishes in the classical plate model. The presence of harmonic forces within the planes of the considered plate increases the natural and resonance frequencies of the plate in free and forced vibrations respectively. Further, the parameter characterizing the transversely isotropic structure of the plate is observed to increase the plate flexural rigidity which in turn increases both the natural and resonance frequencies. Finally, this study reinforces the view that non-classical models of problems in elasticity provide ample opportunity to reveal important phenomena which classical models often fail to apprehend.

• Journal of Korean Association for Spatial Structures
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• v.1 no.1 s.1
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• pp.109-115
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• 2001

Composite materials also known as fiber reinforced plastics have been developed and used in many engineering applications due to their outstanding mechanical properties. Laminated plates as structural components that are made of in composite material are widely used. Therefore, nonlinear response of laminated composite plates modeled with finite elements and excited by stochastic loading is studied. The classical laminated plate theory is used to account for the variation of strains through the thickness for modeling laminated thin plates. Approximate nonlinear random vibration analysis is performed using the method of equivalent linearization to account for material non-linearity.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.1
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• pp.141-146
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• 2012

Aluminum alloys have been used with various thicknesses suitable for light weight of structure. It is known that the thickness effect of material is an important factor affecting fatigue crack propagation under constant fatigue stress condition. In this work, we presented the behavior of fatigue crack propagation in thin plate compared to thick plate Al 2024-T3 alloy with referred thickness effect in a correlative equation determined by the shape factor and the loading factor. We chose two factors that are used in the correlative equation with considering that the experiments were carried out under a constant fatigue stress condition. The thickness ratio of thin plate compared to thick plate and the equivalent effective stress intensity factor ratio depending on thickness were chosen as shape and loading factors. A correlative equation is utilized to determine the equivalent effective stress intensity factor range of thin plate and identify the degree of increasing phenomenon of fatigue life in thin plate compared to thick plate.